Commercial packaged HVACR systems such as rooftop units for servicing large buildings such as office buildings, multi-tenant dwellings, or warehouses, use centrifugal blowers such as plenum fans to drive airflow through the systems. Near a centrifugal blower such as a plenum fan, the airflow may be a horizontal tornado, with a rotation determined by the direction in which the fan is spinning. This can result in uneven pressurization of the fan cabinet and result in uneven flow through heating elements attached to the fan cabinets which are used to heat buildings. This uneven flow may require a larger cabinet to allow airflows to normalize before the airflow passes through heating elements used to heat the air then supplied to a building by the HVACR system, causing the HVACR system to be larger than necessary and limiting the building which can be serviced by the HVACR system.